Broadcast to raise a smile (4)

I believe the answer is:

beam

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'a smile' is the definition.
(to beam is to smile)

I don't understand the rest of the clue.

(Other definitions for beam that I've seen before include "Sturdy timber" , "Big smile; ray" , "Shine" , "Smile widely; ray" , "Give a wide smile" .)

I've seen this clue in The Globe and Mail.

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